In 1946, a U.S. Army Lieutenant surveying damage left by the massive explosion of the first atomic bomb in Hiroshima sent a letter to a safe-making company back in America. “I found in one of three structures standing, four large vaults built by the Mosler Safe Co. of Hamilton, Ohio,” he explained. “The vaults were entirely intact and except for the exterior being burned and rusted there was no damage.” Two other vaults he added, made by a Toyko, Japan company, were completely destroyed.

The two-story Teikou Bank built in 1925 was close to the hypocenter of the blast. Made of steel and concrete, the building crumpled from the inside, cracking the exterior and tearing the cement floor to bits. Nearly two dozen employees were in side at the time. None survived.

But the bank vaults did.

This was reassuring news at least to bank executives back in the States. At the time there was a heightened sense of security against attacks on American soil. Many banks advertised that valuables were better protected because they used Mosler safes.

Even the U.S government chimed in. Mosler was awarded a lucrative contract and eventually built a 25-ton blast door vault in West Virginia mountainside bunker used to hide classified and historical documents.

Then five years after the attack, Mosler received another letter. This time it was from the manager of the newly rebuilt Teikou bank in Hiroshima. “Your products are admired,” he praised, “for being stronger than the atomic bomb.”

In the late 1950’s, to recreate the same show of strength displayed in Hiroshima, Mosler took their products to the Yucca Flats nuclear testing grounds in the Nevada desert. They placed a Century steel door and concrete vault with various contents in the blast zone.